5.56 ammo

OK so I popped for a new AR15. 16" barrel, 1 in 7 twist. Bought it primarily as a range toy but what's the best heavy weight ammo for self defense purposes?
Please keep in mind that I'm an old fart whose definition of an assault rifle is a 1894 marlin in 44mag.
Doubt I'll ever use it on anything but targets, might come in handy for skunks.

You don't necessarily "need" a heavy bullet for self defense. We used the 77 grain black hills in the military, but mostly for the improved accuracy at longer distances than anything foreseeable in a defensive situation. I would just shop for some law enforcement ammunition from a company like Hornady, and focus on the reliability and accuracy of that round, insuring that it groups and properly stabilizes in YOUR gun within 25 meters or so. Plan to expend 1 box for testing, and then buy however much you want to keep on hand for emergency use.

5.56 isn't legal for deer hunting in my neck of the woods and I consider it a poor choice compared to a 30/06 or even a 30/30.
Heck I think a blackie would really get pissed off if it got shot with one.

For personal defense and target use, the Black Hills Mk 262 or other loads with the 77 gr MatchKing, and other loads with the heavy OTMs like the 75 gr Hornady are probably going to be your best bet.

With the heavier Barnes, like the 70 gr TSX, you might be surprised what the lowly 5.56 can do. After seeing what the 62 gr Barnes Vortex can do, I am convinced it will do anything the .243 Win with traditional cup-and-core JSP can do.

Personal defense is really short range stuff - like across a room. Walls in homes are not bulletproof and penetrating through them is a real danger to non-bad guys. Now I know this goes against the current dogma, but maybe the same ammo for skunks outside is good for skunks inside, too. Light weight high speed varmint bullets, 36 to 45 grain tnt or polymer tipped. I have seen exactly what they do to deer during a large cull shoot and although its not good for anything that requires deep penetration, it certainly can be lethal and probably a lot better for loved ones in the next room over.

The Barnes 62gr TSX and 70gr TSX are known to work well on game, and I’ve heard unsubstantiated claims that two legged upright vermin are suitably smited by them as well. I know that out of my 1:7” twist cold hammer forged chrome lined 16” Knight’s Armament SR-15 E3 Mod 2 that the 70gr Barnes stabilizes just fine and gives 5 shot groups of 1.25”-1.5” at 100 yards using a 4X optic that is not optimized for shooting groups.

Downsides are cost, and over penetration concerns since they are all copper. Also note that the 5.56mm 70gr TSX load is reported to be pretty hot, and they’re not kidding about the warning to run it in 5.56mm NATO chambers. A friend of mine bought some to run in his 1:8” Rock River with a .223 Wylde chamber: it flattened primers, and had signs of brass flow into the ejector with nasty extractor swipes on the rim. The 1:8” twist also didn’t stabilize the bullet well enough to give good accuracy, his groups were around 5”-6” at 100 yards. My carbine shot it well, ejected brass into a nice consistent area, and the brass looks like it came out of a bolt gun. I bought the rest of his supply of this ammo, and he tried the 62gr TSX 5.56mm load and it worked great, including visual pressure signs on his brass. I suspect his chamber is too tight, and the throat is too short, and the long (longer than a 77gr SMK!) all copper 70gr bullet was jacking pressures up at full 5.56mm NATO loading.

Also worth a look is the FBI carbine duty load, Federal XM556SBCT3 (62gr bonded core). It meets all their criterion for barriers, expansion, penetration etc. Not sure how available it is to non LEO buyers though.

I live in a Florida block home, what’s with this talk of wall penetration? I’m more likely to be hit by a ricochet from a light bullet than something coming through my walls. That’s why I use crushed pop bottle in 12g shells. Just sweep up later.
As to accuracy a 1:7 twist is geared towards a 70+g bullet for accuracy. The slower the twist, the heavier the projectile. Just like 1:9 is geared for 60+g which is what we used in the service back in the day.
And if I’m not mistaken old m4 clones where 1:13 for 50+g , but I am not 100% certain on that.

I live in a Florida block home, what’s with this talk of wall penetration? I’m more likely to be hit by a ricochet from a light bullet than something coming through my walls. That’s why I use crushed pop bottle in 12g shells. Just sweep up later.
As to accuracy a 1:7 twist is geared towards a 70+g bullet for accuracy. The slower the twist, the heavier the projectile. Just like 1:9 is geared for 60+g which is what we used in the service back in the day.
And if I’m not mistaken old m4 clones where 1:13 for 50+g , but I am not 100% certain on that.

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Actually, it is the faster the twist, the heavier the projectile. And it actually has more to do with bullet length than bullet weight. It just so happens that in a given caliber, heavier bullets tend to be longer than lighter bullets of similar construction. But a 1:7 twist is faster than a 1:9 twist because it completes one revolution in just seven inches, which is faster than nine inches.

Actually, it is the faster the twist, the heavier the projectile. And it actually has more to do with bullet length than bullet weight. It just so happens that in a given caliber, heavier bullets tend to be longer than lighter bullets of similar construction. But a 1:7 twist is faster than a 1:9 twist because it completes one revolution in just seven inches, which is faster than nine inches.

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I stand corrected and if anyone could have gotten it backwards it’s me as it’s been over 20 years since I’ve held an EBR. Perhaps one day soon I’ll fix that...

OK so I popped for a new AR15. 16" barrel, 1 in 7 twist. Bought it primarily as a range toy but what's the best heavy weight ammo for self defense purposes?
Please keep in mind that I'm an old fart whose definition of an assault rifle is a 1894 marlin in 44mag.
View attachment 825342
Doubt I'll ever use it on anything but targets, might come in handy for skunks.
View attachment 825343

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If you want a bullet that will self destruct once it hits it's target and not continue on and hit the neighbors house but delivers all of it's energy on the target I suggest some 55 grain Nosler Varmageddons or Hornady SX's. The 1/7 twist is pretty fast but the Varmageddons and SX's should hold together as long as they are not at max load coming out of a long barrel.

The Barnes 62gr TSX and 70gr TSX are known to work well on game, and I’ve heard unsubstantiated claims that two legged upright vermin are suitably smited by them as well. I know that out of my 1:7” twist cold hammer forged chrome lined 16” Knight’s Armament SR-15 E3 Mod 2 that the 70gr Barnes stabilizes just fine and gives 5 shot groups of 1.25”-1.5” at 100 yards using a 4X optic that is not optimized for shooting groups.

Downsides are cost, and over penetration concerns since they are all copper. Also note that the 5.56mm 70gr TSX load is reported to be pretty hot, and they’re not kidding about the warning to run it in 5.56mm NATO chambers. A friend of mine bought some to run in his 1:8” Rock River with a .223 Wylde chamber: it flattened primers, and had signs of brass flow into the ejector with nasty extractor swipes on the rim. The 1:8” twist also didn’t stabilize the bullet well enough to give good accuracy, his groups were around 5”-6” at 100 yards. My carbine shot it well, ejected brass into a nice consistent area, and the brass looks like it came out of a bolt gun. I bought the rest of his supply of this ammo, and he tried the 62gr TSX 5.56mm load and it worked great, including visual pressure signs on his brass. I suspect his chamber is too tight, and the throat is too short, and the long (longer than a 77gr SMK!) all copper 70gr bullet was jacking pressures up at full 5.56mm NATO loading.

Also worth a look is the FBI carbine duty load, Federal XM556SBCT3 (62gr bonded core). It meets all their criterion for barriers, expansion, penetration etc. Not sure how available it is to non LEO buyers though.

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I can vouch for the good performance of the 70gr Barnes TSX out of both 16" and 11.5" 1-7 twist barrels.

The point of going with the heavier projectiles isn't necessarily the range or the accuracy. The heavy match projectiles tend to be very consistent all the way around. This makes their performance consistent and predictable. The long range match bullets have thin jackets and the way they are constructed with the air cavity in the nose makes them base heavy, which exaggerates their tendency to yaw in tissue. Upon yawing, the thin jacket is prone to fracturing and the bullet fragments reliably above about 2200 fps. In fact, some of the most successful use of rounds like the Mk 262 with the 77 gr Sierra OTM within the military community has been from short barreled sub-carbines like the Mk 18. These short barreled carbines are handy indoors but the reduced velocity can lead to problems from harder projectiles. The OTM rounds behave similar to the varmint rounds but actually achieve adequate penetration reliably while providing often 50% more material for fragmentation. Simply put, they are just more effective than varmint rounds.

The fact that they achieve the best external ballistics and long range accuracy in addition to ideal terminal performance is just icing on the cake.

The terminal ballistic performance of heavier projectiles may be markedly different from that of lighter projectiles, even when the two different cartridges are made by the same manufacturer with the same general projectile design.

As an example, on youtube an individual posted his results with Hornady Critical Defense .223 Remington in the 55 grain and 73 grain versions using the same testing protocol and same rifle. He used 10% clear ballistic gelatin with and without 4 layers of denim using a Daniel Defense 5.56 rifle with a 16" barrel with 1:7 twist rate. Both cartridges had the Hornady FTX flex-tip projectile design. Gel blocks were shot at 10 ft range.

The 55 grain cartridge only managed around 8 1/2 - 9 inches of penetration in clear gel with or without the denim barrier. The 73 grain version demonstrated around 13" of penetration in bare gelatin and around 12 1/2" through 4 layers of denim. Many would not consider less than 10" of penetration to be adequate for a self-defense cartridge.

If you are interested in viewing these tests, here is the link to the 55 grain test (the 73 grain test is easily found):

The 55 grain cartridge only managed around 8 1/2 - 9 inches of penetration in clear gel with or without the denim barrier. The 73 grain version demonstrated around 13" of penetration in bare gelatin and around 12 1/2" through 4 layers of denim. Many would not consider less than 10" of penetration to be adequate for a self-defense cartridge.

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Not to go off in the weeds, but folks should remember the purpose of gel penetration tests had to do with adequate penetration of handgun bullets for FBI standards. High velocity rifle rounds create very different wounds with large stretch cavities. A minimal upset 45 or 9mm traveling 10 inches in gel is nothing like a high velocity frangible rifle bullet doing the same. Lots of real world data have proven that over and over.

A lot of real world experience with 5.56x45 and 7.62x39 FMJ rifle wounds has demonstrated that when these high velocity projectiles do not yaw, tumble, or fragment after striking tissue, they may do little more than drill a neat .22 caliber hole through and through, despite delivering great kinetic energy and no doubt creating large stretch cavities.

Large stretch cavities in human soft tissues do not necessarily result in extensive tissue destruction, a lesson which was painfully learned by civilian trauma surgeons in the US when they first encountered these wounds. Many extensive debridements were done as a knee jerk response, a good number of which were unnecessary. Eventually those who encountered these wounds learned that in the absence of obviously devitatlized tissue, conservative surgical treatment was indicated, and usually was sufficient. At that point, the surgical dictum became "treat the wound, not the weapon".

Some argue that the large temporary stretch cavities result in some type of temporary incapacitation even in the absence of any tissue destruction that would be evident later. But US servicemen during the battle of Mogadishu and other conflicts, reported seeing their 5.56 FMJ rounds go right through the torsos of the slender Somalis without apparent affect, because the tissue path was of insufficient length to start them tumbling.

A lot of real world experience with 5.56x45 and 7.62x39 FMJ rifle wounds has demonstrated that when these high velocity projectiles do not yaw, tumble, or fragment after striking tissue, they may do little more than drill a neat .22 caliber hole through and through, despite delivering great kinetic energy and no doubt creating large stretch cavities.

Large stretch cavities in human soft tissues do not necessarily result in extensive tissue destruction, a lesson which was painfully learned by civilian trauma surgeons in the US when they first encountered these wounds. Many extensive debridements were done as a knee jerk response, a good number of which were unnecessary. Eventually those who encountered these wounds learned that in the absence of obviously devitatlized tissue, conservative surgical treatment was indicated, and usually was sufficient. At that point, the surgical dictum became "treat the wound, not the weapon".

Some argue that the large temporary stretch cavities result in some type of temporary incapacitation even in the absence of any tissue destruction that would be evident later. But US servicemen during the battle of Mogadishu and other conflicts, reported seeing their 5.56 FMJ rounds go right through the torsos of the slender Somalis without apparent affect, because the tissue path was of insufficient length to start them tumbling.

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FMJ is required by the rules of law for war, and aides greatly in functioning of machine guns. It would certainly not be the best first choice for self-defense or anything else that required immediate lethal results. Deep straightline penetration is important, but reliable expansion or fragmentation makes the real differences.

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